Health care workers at hospitals, nursing homes, and home care programs face the challenge of moving partly or completely incapacitated patients. A typical patient weighs between 45 and 90 kilograms, although many others weigh much more. Consequently, at least two to four health care workers are usually needed to move the patient. These activities often create unacceptable risks of injury, almost without regard to the number of health care workers used in the patient transfer. The risks are particularly high when a sufficient number of workers is not available to assist in a patient transfer. For example, injuries to workers' backs account for approximately 50% of worker's compensation costs for workplace injuries in the health care industry in the United States, and thus are a particularly vexing problem.
Patient transfers can be placed in several broad categories. A first category includes the horizontal transfer of a patient from one flat surface to another. A second category involves upright transfers where a patient is moved from a horizontal position to an upright or sitting position in a wheelchair, chair or commode, and the return of the patient to the horizontal position from an upright or sitting position. A third category of transfer relates to the positioning or movement of patients in order to change their position in a bed or chair, for example pulling the patient up in the bed or rolling the patient from side to side. Although many attempts have been made to devise improved systems for patient transfer, almost all of these transfers continue to be manually performed.
Current healthcare guidelines typically recommend that four health care workers participate in a patient transfer. Two workers are at the bed side and two workers are at the cart side. Each worker grabs an edge of a draw sheet, which is positioned under the patient. The patient is then transferred between the bed and the cart through a combination of lifting, pulling, and pushing. An elongated plastic sheet is often placed beneath the patient to reduce friction or drag. Since a health care worker has to bend over at the waist to accomplish these patient transfers, the stresses encountered are magnified well beyond what would otherwise be expected for a maximum recommended lift of approximately fifty pounds. Normally this recommended maximum lift is measured with the lift at or near the worker's center of mass. Extremes in a health care worker's height, either taller or shorter than average, or any weakness in either the arms or legs further exaggerate these risks.
Many hospitals have swing-type mechanical lift devices to assist in certain patient transfers. However, these devices are not widely used because they are often cumbersome and time-consuming to set up and operate. Depending on the lift required, the devices may also be inappropriate.
The upright transfer and positioning categories provide similar difficulties, especially if the patient is unable to cooperate. For example, weak and elderly patients reclining in a semi-erect position tend to slide down. These patients must be returned to a position more toward the head of the bed. To do so, two health care workers usually grasp the patient by the upper arms to hoist the patient toward the head of the bed after the bed has been lowered to a more horizontal position. This manual transfer often causes strain on the workers' upper and lower backs and possible contact bruises on the patient. Similar difficulties occur with upright transfers.
Given these formidable difficulties, there have been other attempts to mechanize the patient transfer process. For example, U.S. Pat. No. 2,665,432 (Butler), describes a cart with a manual crank connected to an extensive pull unit. The pull unit has a large number of straps which connect at an edge by hooks to a transfer sheet. Rotation of the crank winds the pull unit onto a roller. The size of the pull unit presents many difficulties including its attachment at many locations to the sheet and the awkwardness of winding it on the roller. The pull unit must be placed under the patient just prior to transfer, since it would not normally be kept there otherwise. Also, no means are provided for transferring the patient off the cart.
U.S. Pat. No. 2,827,642 (Huff) describes a similar system mounted to the head of a bed and designed to move a patient from the foot toward the head of the bed. The '642 Patent does not describe the process of moving a patient laterally from one horizontal surface to another.
U.S. Pat. No. 4,970,738 (Cole) discloses another patient transfer system which employs a manual crank and self-locking gear system. This system has an advantage over the system described in the '432 patent in that the transfer is reversible. Rotating the crank drives a belt system, which is attached to a semi-rigid transfer apron. The apron is thereby transferred horizontally while supporting a patient. This system has the disadvantage that the apron must be first positioned under the patient before the patient can be transported from a bed onto a cart. Another disadvantage is that the transfer support alone does not provide sufficient support for the patient or the transfer system. Because of the complexity of its design, considerable operator interaction would be required for the transfer support to be mounted to a cart and then operated to transfer a patient.
U.S. Pat. No. 2,733,452 (Tanney) describes a transfer system that uses a motorized pulley to transfer a patient on a metal-reinforced transfer sheet. The transfer sheet has metal grommets in its corners for attachment to cables. A motor is used to wind the cables onto reels thereby resulting in the transfer of the sheet and the patient thereon. However, the patient must first be moved onto the transfer sheet before being moved from a bed to the cart. Moreover, this invention fails to provide support beneath a patient being transferred thereby.
U.S. Pat. Nos. 4,747,170 and 4,868,938 (both to Knouse) reveal a motorized winch-type transfer system. This transfer system has apparent advantages over the transfer system of the '452 patent, which include a more secure transfer sheet gripping mechanism and the use of a transfer sheet which does not need grommets or other similar devices. Though more secure, the gripping system is difficult and awkward to use.
U.S. Pat. No. 5,038,424 (Carter et al.) teaches a system for reciprocally transferring a patient between a bed and a cart. This system employs a pliable transfer web wound about two detachable, cylindrical rollers and a drive motor mounted on the bed and the cart. In use, the bed and cart are positioned side-by-side and the web is placed beneath the patient. The roller adjacent the cart or bed onto which the patient is to be transferred is detached. While unwinding a sufficient length of transfer web wound thereon, the roller is extended to the opposite side of the bed or cart onto which the patient is to be transferred, and there connected to the drive motor. The drive motor is then activated, thereby rewinding the transfer web onto the roller and transporting the patient disposed thereon. Thus, while enabling reciprocal transfer, the system of the '424 patent is time consuming and awkward to set up. Moreover, as in the previous inventions discussed hereinabove, the patient is not supported adequately while being transferred.
While considerable effort has gone into developing horizontal patient transfer systems, all of the systems previously developed have significant drawbacks. These drawbacks primarily relate to the significant difficulties encountered in set-up and operation.
The patent described hereinabove primarily relate to systems for transferring patients from one horizontal surface to another horizontal surface. By partial contrast, U.S. Pat. Nos. 4,700,415 and 4,837,873 (both to DiMatteo et al.) teach a system for transferring patients between a reclined wheelchair and a bed. The bed is equipped with a sheet wound about a right side roller and a left side roller, the sheet positioned beneath a patient reclining thereupon. The right and left side rollers are positioned laterally on each side of the bed, usually slightly below the plane of the patient. Two corner rollers are situated above the right side and left side rollers and approximately level with the top surface of the bed. The reclined wheelchair is equipped with two articulated rollers. Extending between these rollers is a sheet, the sheet including three bands. The lateral edges of the sheet may be joined or separate. If the lateral edges are to be joined, the sheet spans above and below the wheelchair upper surface. If the lateral edges are free, the sheet spans the wheelchair upper surface, its ends wound about the two rollers. The separate transfer systems for the bed and wheelchair must be powered such that both sheets rotate with equal velocities. In use, the patient reclining upon the bed is conveyed laterally by the bed transfer system. Upon encountering the wheelchair transfer system, the patient is thereupon further conveyed onto the wheelchair. The wheelchair may then be further adjusted, allowing the patient to assume a sitting position.
While the system of DiMatteo allows for transfer to or from a reclining wheelchair and for adjusting the wheelchair between sitting and reclining positions, its shortfalls include the complexity of its design, the need to retrofit beds with the rollers and sheet provided, and the possibility of pinching the patient or catching clothing in the gaps between the bands.
U.S. Pat. No. 3,597,774 (Warren) describes a harness and winch mechanism for raising a patient reclining upon a bed. The winch is mounted to a post attached to the head of the bed and is operated by a hand crank. The harness loops under the patient's armpits such that excessive stress may be applied thereto during operation of the device.